Morphological Variation of the Mandible in the Orthognathic Population-A Morphological Study Using Statistical Shape...

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Orthodontics

Background:

• Orthognathic surgery planning requires precise understanding of craniofacial morphology.
• Objective quantification of mandibular shape variations is crucial for personalized surgical approaches.
• Existing methods may not fully capture subtle shape differences between patient demographics.

Purpose of the Study:

• To evaluate the utility of 3D Statistical Shape Modelling (SSM) in orthognathic surgery planning.
• To objectively characterize mandibular shape variations within the orthognathic population.
• To identify and quantify shape differences between male and female mandibles.

Main Methods:

• Utilized pre-operative cone-beam computed tomography (CBCT) scans from 194 orthognathic surgery patients.
• Developed 3D virtual surgical plans (3D VSP) and automatically segmented 3D mandibular models.
• Constructed a statistical shape model using principal component analysis (PCA) and performed unpaired t-tests for sex comparisons.

Main Results:

• The first five principal components described key mandibular shape features: ramus height, gonial angle, ramus width, chin projection, and condylar/ramal distances.
• Significant differences in mandibular shape were identified between male and female patients across 10 principal components.
• SSM proved feasible for visualizing and quantifying population-specific and sex-related mandibular morphology.

Conclusions:

• 3D Statistical Shape Modelling is a valuable tool for objective analysis in orthognathic surgery.
• The study successfully identified distinct male and female mandibular shape characteristics.
• Findings can enhance surgical planning for mandibular shape modifications and improve patient outcomes.